A conventional cylinder lock includes two knobs respectively formed inside and outside a door, in which either knob can be rotated for opening the lock when a correct key is inserted in the pin tumblers. However, such a conventional cylinder lock may still have the following drawbacks:
1. Either outer or inner knob should be rotated for opening the door. If the rotation angle for example one turn of 360 degrees is not enough, the door may not be opened, which is not suitable for an emergency escape.
2. It is not convenient for opening the door by someone whose two hands already carries a goods.
3. The cylinder lock once being locked may still be intentionally opened by an intruder who uses an auxiliary tool such as a pipe wrench, since the cylinder handle is secured with the locking latch.
The present inventor has found the drawbacks of a conventional cylinder lock and invented the present cylinder lock operated by push or pull action.